This hike starts just outside Huaraz at the Wilcacocha bridge. You begin at about 3,100m and ascend to over 3,700m. We were told it usually takes between three and five hours there and back. Five hours turned out to be more accurate for us. I think you'd have to be super fit to do this walk in less than five hours.
The bus from Huaraz leaves from the corner of Hualcan street and Antonio Raymond costing 3PEN. It took fifteen minutes to reach the bridge where we asked the driver to stop. There’s a small shop just over the bridge where you can buy bottled drinks before you leave.
The walk is steep but not too difficult. There's a winding road going up the mountain and a footpath going straight up. The path crosses the road many times as it weaves back and forth. We took a combination of road and trail and arrived at the lake around midday.
It wasn’t a particularly large lake. I would estimate roughly 100m by 50m. There were lots of little blue-billed ducks paddling on its surface, and the best thing was the view of the valley, very nice.
On the way back, we were lucky enough to witness a Tarantula Hawk (a giant wasp with a powerful sting) locked in battle with a spider. Actually, the battle was over, and the spider had lost. It was being dragged off by its face to have eggs laid inside its paralysed body. Nature can be gruesome.
In summary, this hike was just what the local guidebook said, "a good acclimatisation walk." If you're lucky enough to be in Huaraz and have the time, it's a nice way to spend a day. If your time is limited or you've already acclimatised, you could give this one a miss and try one of the longer hikes to Lake Churup, or Lake 69.